package com.diaohaiwen.framework.web.util;

import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.SneakyThrows;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import java.io.InputStream;
import java.net.URLEncoder;

/**
 * @author 刁海文
 * @since 2023/11/29 20:39
 */
public class RequestUtil {

    public static HttpServletRequest getRequest() {
        ServletRequestAttributes attr = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        assert attr != null;
        return attr.getRequest();
    }

    public static HttpServletResponse getResponse() {
        ServletRequestAttributes attr = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        assert attr != null;
        return attr.getResponse();

    }


    public static String ip() {
        HttpServletRequest request = getRequest();
        String ip = null;

        //X-Forwarded-For：Squid 服务代理
        String ipAddresses = request.getHeader("X-Forwarded-For");

        String unknown = "unknown";
        if (ipAddresses == null || ipAddresses.length() == 0 || unknown.equalsIgnoreCase(ipAddresses)) {
            //Proxy-Client-IP：apache 服务代理
            ipAddresses = request.getHeader("Proxy-Client-IP");
        }

        if (ipAddresses == null || ipAddresses.length() == 0 || unknown.equalsIgnoreCase(ipAddresses)) {
            //WL-Proxy-Client-IP：weblogic 服务代理
            ipAddresses = request.getHeader("WL-Proxy-Client-IP");
        }

        if (ipAddresses == null || ipAddresses.length() == 0 || unknown.equalsIgnoreCase(ipAddresses)) {
            //HTTP_CLIENT_IP：有些代理服务器
            ipAddresses = request.getHeader("HTTP_CLIENT_IP");
        }

        if (ipAddresses == null || ipAddresses.length() == 0 || unknown.equalsIgnoreCase(ipAddresses)) {
            //X-Real-IP：nginx服务代理
            ipAddresses = request.getHeader("X-Real-IP");
        }

        //有些网络通过多层代理，那么获取到的ip就会有多个，一般都是通过逗号（,）分割开来，并且第一个ip为客户端的真实IP
        if (ipAddresses != null && ipAddresses.length() != 0) {
            ip = ipAddresses.split(",")[0];
        }

        //还是不能获取到，最后再通过request.getRemoteAddr();获取
        if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ipAddresses)) {
            ip = request.getRemoteAddr();
        }

        return ip;
    }


    @SneakyThrows
    public static void download(InputStream stream, String contentType, String filename) {
        HttpServletResponse response = getResponse();
        response.setContentType(contentType);
        response.addHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
        ServletOutputStream outputStream = response.getOutputStream();
        byte[] b = new byte[1024];
        int len;
        //从输入流中读取一定数量的字节，并将其存储在缓冲区字节数组中，读到末尾返回-1
        while ((len = stream.read(b)) > 0) {
            outputStream.write(b, 0, len);
        }

        stream.close();
    }
}
